Enviropig
Background The Enviropig is a genetically modified strand of Yorkshire Pig that has an increased ability to breakdown plant phosphorus. This GMO was produced at the University of Guelph in the 1990s. These pigs now produce the enzyme phytase in their salivary glands which is later secreted into the digestive tract in saliva (Enviropig 2010.) The pigs were only shown to produce trace amounts ( <0.1%) of the phytase enzyme in other tissues (Streiffer 2002.) The primary diet of farm-raised pork is composed of corn/barley, soybean meal, trace minerals/vitamins and supplemental phosphorus, and in a normal pig this creates feces that is heavily laden with phosphorus. 50% to 70% of the naturally occurring phosphorus in the food is found in the phytate (phytic acid) form and is indigestible by wild type Yorkshire pigs. Therefore, farmers must supplement phytase into the diets of pigs along with a more digestible form of phosphorus. Enviropigs produce and utilize phytase to digest the phytic acid and therefore reduce the concentration of phosphorus in feces by up to 75%. This process is also economically favorable because dietary supplementation with mineral phosphate or commercially produced phytase is no longer required (Enviropig 2013.) The manure exhibits further environmental benefits because phosphorus is the major nutrient for algal growth and it has been shown to leak into rivers and streams proximal to livestock farms (Streiffer 2002.) Excess phosphorus in aquatic environments results in algal booms that wipe out native species and destroy the biodiversity of ecosystems. So overall, the enviropig has the potential to reduce herd maintenance costs while producing a less harmful byproduct. Phytate Known as inositol hexakisphosphate (IP6) or phytate when in salt form, Phytate is a saturated cyclic acid and is the primary storage form for phosporus in plant tissues. This compound is indigestible by humans for nonruminant animals, and has been known to increase the difficulty by which zinc and iron are absorbed (Phylic 2013.) The chemical formula for this compound is C6H18O24P6. How to make an Enviropig A transgene is constructed linking a portion of the mouse gene responsible for salivary protein production in the parotid, sublingual and submaxillary glands to a phytase gene from E. Choli. This transgene was introduced into ferilized pig stem cells via electroporation, selected for, and later implanted into pseudopregnant surrogate sows. This lead to the production of chimeric piglets that did not necessarily have the germline mutation for phytase production. These piglets were then bred with wild-type yorkshire hogs until the germline mutation was acheived. The piglets produced were tested for the gene by sampling the saliva for the phytase enzyme and also my DNA analysis (Steiffer 2002.) In February of 2010 the Department of the Environment of the Canadian Government determined the Enviropig to be in compliance with the Canadian Environmental Protection act (Enviropig 2013). This allowed enviropigs to be bred in controlled facilities. Ontario Pork ended their support for the Enviropig in April of 2012 and all of the pigs were killed two months later after they failed to find new funding for the program. The genetic material is now being stored at the Canadian Agricultural Genetics Repository Program (Enviropig 2013.) Works Cited #"Enviropig ." Commercialization & Regulatory. University of Guelph, 2010. 09 Oct. 2013. #Enviropig . (2013, June 27). In Wikipedia, The Free Encyclopedia. Retreived Octover 9, 2013. #Streiffer, Robert and Sara Ortiz. "Ethical Issues Arising from Enviropigs." New Perspectives in Agricultural Biotechnology . University of Wisconsin, 19 Nov. 2002. Web 9 Oct. 2013. #Phytic acid . (2013, October 12). In Wikipedia, The Free Encyclopedia. Retrieved Oct. 14 2013.